ancel keysAncel Keys was a prolific American scientist who is best known for his early work on heart attack risk factors and his theory that dietary saturated fats raise cholesterol to cause heart attacks.  His other lasting contributions include K-Rations, the Body Mass Index (BMI) and the Mediterranean Diet.
In the early 1950s, he recognized correctly that red meat is associated with increased risk for heart attacks and diabetes.  He spent many years trying to prove that the culprit was saturated fat, but more recent research shows that other components of meat are more likely to be responsible for the association with heart attacks.  Even though some of his theories have been discredited, he helped to prolong many lives by showing that:
• smoking increases risk for heart attacks,
• high blood pressure and high cholesterol can predict susceptibility for heart attacks,
• eating less meat and taking in fewer calories help to prevent heart attacks,
• the traditional Mediterranean diet (high in plants and fish) helps to prevent heart attacks, and
• most heart attacks are preventable.
Early Life 
Ancel Benjamin Keys was born on January 26, 1904 and died on November 20, 2004. He hated high school, so he ran away from his home in California to Arizona, where he found work shoveling bat guano out of caves and putting it in bags to be sold as fertilizer. He decided that school was better than shoveling bat manure, so he enrolled at the University of California at Berkeley. He went on to receive a PhD in biology from UC at the Scripps Institute in La Jolla CA. In 1935, he organized an expedition to the Andes mountains to study how living in the oxygen sparse air at 20,000 feet affects humans.
In 1941, he went to work for the United States War Department to design lightweight and nutritious rations for paratroopers, even though he had no training in nutrition.  He went to a grocery store in Minneapolis and bought hard biscuits, dry sausages, hard candy and chocolate bars. He mixed them together to form a hard, gummy food that had lots of calories and would keep for a long time. His first food packs for the troops were called C- and D-rations, with 3200 calories in a 28-ounce packet.  The most popular formula was called K-rations, which tasted so bad that Dr. Keys spent the rest of his life denying that K-rations were named after him.

High Blood Pressure, High Cholesterol and Smoking 
After the war, Dr Keys set out to explain why the wealthiest U.S. citizens, the businessmen and professionals, were the ones most likely to die from heart attacks.  He ended up at the University of Minnesota where he conducted his "Twin Cities Study" and found that high blood pressure, high cholesterol and smoking were major risk factors for heart attacks. Heart attacks occurred most commonly in those who were the fattest, ate the most meat, exercised the least and smoked.
His research showed that dietary cholesterol was not associated with increased risk for heart attacks. More than 80 percent of the cholesterol in your body is made by your liver, while less than 20 percent comes from the food that you eat. When you take in more cholesterol, your liver makes less. When you take in less cholesterol, your liver makes more.  However, most of the scientific community ignored Keys’ work on cholesterol and decided incorrectly that dietary cholesterol was an important factor in raising blood cholesterol. 
The Flaw in Keys' Saturated  Fat Theory
Keys measured blood saturated fat levels and found that people who had the highest blood levels of saturated fats were at increased risk for developing heart attacks.  However, he did not recognize that saturated fats that you make in your own body are different from the saturated fats that you eat.  Your body contains two types of saturated fats: even chain and odd chain. The largest study of its kind, from the University of Cambridge in the UK, shows that the even-chain saturated fats, which are associated with increased risk for diabetes and heart attacks, are made primarily by the human liver from the sugar and alcohol that you take in.  The odd-chain saturated fats in your bloodstream come primarily from the saturated fats that you eat, and they are not associated with increased risk for heart attacks (Lancet Diabetes & Endocrinology, published online August 6, 2014). In this study, researchers followed 340,234 adults from eight European countries. Using high-speed blood analysis, they measured the types of saturated fats in the bloodstream and found that they could predict who would become diabetic by their high levels of even-chain saturated fats.

Good Foods and Bad Foods
In 1957, Ancel Keys started his “Seven Countries Study” that showed that the Greeks, Japanese and Italians had the lowest rate of heart attacks, while the Finns had the highest rate with North Americans not far behind.  He theorized that the people who ate the most calories and saturated fat and had the highest blood cholesterol levels (Finns and North Americans) were the ones with the highest rates of heart attacks.  He went on to explain that the Greeks and Italians who ate lots of vegetables, seafood, olives and olive oil were protected from heart attacks, and so were the Japanese who ate a lot of deep-water fish. He concluded that fruits, vegetables and fish help to prevent heart attacks  and proposed that the most healthful way to eat was the traditional Mediterranean diet.  
Heart Attacks: Saturated Fat or Sugar?
In the 1950s, John Yudkin was the leading spokesman for the theory that sugar and other refined carbohydrates were harmful. He and Ancel Keys argued continuously, in journals and at medical meetings, about whether sugar or saturated fats were the prime cause of heart attacks. Today, both are heroes. John Yudkin was born in 1910 and died in 1995. Ancel Keys was given much credit and praise during his lifetime for his work on the causes of heart attacks. Only recently has Dr. Yudkin’s theory that excessive amounts of sugar cause heart attacks become accepted, so he did not receive this richly-deserved credit while he was still alive.  
Keys is remembered for showing that red meat is associated with increased risk for heart attacks, although he blamed their saturated fat content as the main cause.  More recent research is suggesting that other factors may be more important, such as Neu5Gc or TMAO
Personal Life
In 1939, Keys married Margaret Haney, a medical technologist who worked for him at the Mayo Foundation,  and they had three children.  They traveled widely and lived in Italy for nearly 30 years.  They co-authored three popular books, including How to Eat Well and Stay Well the Mediterranean Way (1975).  Their Mediterranean diet is perhaps Keys' most lasting contribution to nutrition, although opinions vary widely on exactly what the diet is and why it is healthful (lack of meat? lots of vegetables? olive oil? wine? seafood?).  Their healthful lifestyle worked for Keys; he died just two months short of his 101st birthday.
January 26, 1904 – November 20, 2004